Heretofore, various apparatus for removing relatively large machined chips have been proposed and utilized for treating these chips produced by machine tools. However, these apparatus cannot remove fine chips, which in turn are collected together with a machining fluid in a coolant tank and precipitated therein. Thus, if a large amount of the fine chips precipitates in the coolant tank, the capacity of the tank is insufficient for the coolant, which overflows from the tank. As a result, a fire accident may occur due to the oily property of the coolant. Futher, circulation of the unremoved chips together with the coolant may block an ejecting nozzle for the coolant, thereby to cause damage of the tools and reduced quality of the machined products. Futhermore, a settling disorder may arise in a machining center upon replacement of automatic tools, thereby adversely affecting the machining accuracy.
In view of the foregoing, an apparatus of such a type has been proposed that a conventional coolant tank is provided at its inner bottom with a screw conveyor for removing the precipitated chips therefrom. In such type of apparatus, however, the conveyor was generally arranged horizontally in consideration of its conveying capacity and was impossible to be arranged obliquely for the purpose of reducing the settling area.
Since most of the machined chips are generally magnetic in nature, an apparatus provided at its bottom with a magnetic plate has also been proposed to aggregate the magnetic chips at the bottom within the tank, from which they are scraped and removed by a scraper. Such apparatus, however, necessitates also enlargement of the settling area for the magnetic plate in order to increase the aggregation, thereby requiring a large size of the scraper. Thus, the apparatus has a further disadvantage in that only a very limited amount of non-magnetic chips may be removed.
For solving the foregoing problems, there has been proposed an apparatus for filtering the chips from chip-containing liquid, such as a coolant, by use of a filtering means, such as a screen, and transporting the chips on a screw conveyor, as disclosed in U.S. Pat. No. 3,585,924. However, with the apparatus of such type it often becomes unable to filter the chips due to adhesion and clogging of the chips on the screw conveyor for cleaning the filtering means, resulting in a time-consuming, troublesome and inefficient operation.
Accordingly, it has long been needed to provide an apparatus for treating chips, which is compact and achieves efficient recovery and removal of the chips, as well as reduction of the equipment cost.
It has now been found that suspended and precipitated solids in liquid may be surely filtered by arranging a filtrate vessel adjacent to one side of a receiving vessel for a solid-containing liquid, providing a rotatable disc screen between the receiving vessel and the filtrate vessel for causing these vessels to communicate with each other, and arranging an ejecting nozzle for ejecting a washing fluid which is directed against the screen from its filtrate vessel side, resulting in the effective cleaning of the screen and thus efficient operation of the apparatus.
Due to its ability to perform effective and continuous filtration of the solids through the screen, the apparatus may be compact in construction and have the ability to treat a large quantity of the liquid containing chips. Further, the compactness of the apparatus requires less volume and less space for its accommodation.
Accordingly, an object of the invention is to provide an apparatus for separation of solids from a liquid, which has the advantages of compactness, efficient filtration, convenient maintenance, small space for placement, and reduced cost of equipment.